1. Field of the Invention
The present invention relates generally to siding panels and more particularly, a siding panel having a latched nail hem for securing the siding to a structure.
2. Description of the Related Art
Vinyl or metal siding is increasingly used as a convenient and relatively inexpensive covering for residential and commercial buildings. Generally, siding is formed with a nailing strip, or single-ply nail hem, having preformed apertures for accepting a mounting nail or the like at the top of each section of siding to fasten the siding to the structure. A problem with the use of a single-ply nailing strip is that during the manufacture of the siding, edge portions of the siding tend to thin by tapering downwardly. Over time, repeated exposure to wind load may cause the mounting nail to tear through this thin portion of siding at the aperture, resulting in damage to the siding and, possibly, to the structure. Further, this thinning of the siding at the single-ply nail strip may also cause the aperture to weaken and thus stretch, which results in the siding pulling out over the mounting nail.
Another concern with single-ply nail hems is problems resulting form improper installation. Specifically, installing the mounting nails such that the nails are tight against the siding causes the siding panel to buckle with changes in temperature.
In an effort to remedy this problem, siding has been formed with a double-ply nail strip, i.e. a nail hem, by folding the nailing strip over on itself, as shown in FIG. 1, and ending in a free end. In the more effective double-ply nail hems, the free end extends downwardly a considerable extent and apertures are provided in both plies of the nail hem. As the siding is mounted to the structure, the fasteners extend through both nail plies. The double-ply nail hem is formed such that each ply is separated by a small span, and the fasteners, when properly installed, are not completely sunk, thus maintaining the span gap between the two plies of the nail hem. The siding is thereby allowed to glide the span between the two plies of the nail hem to compensate for the effect of wind, without the siding tearing through the fasteners.
The double-ply nail hem offers a dramatic increase in wind-load resistance. However, the concern of tight nailing still exists, which affects the panels ability to expand and contract. Further, the curl of the nail hem is susceptible to stress relaxation, which causes the outer ply to move outwardly and exert pressure against the fasteners and hindering the proper expansion and contraction of the panel. Further, there is limited control for the curl spacing during manufacture. The imprecise control over the span between the laminae lessens its effectiveness to withstand wind load and more specifically lessens the panel""s ability to expand and contract due to temperature changes.
Thus, a need exists for a siding panel having a nail hem that is effective against stress relaxation and improper placement of fasteners.
It is an object of the present invention to provide a siding panel that withstands the stresses due to stress relaxation. It is further an object of the present invention to provide a siding panel that withstands extreme wind load applications, without comprising the panels ability to expand and contract in reaction to temperature change.
The siding panel of the present invention solves the problems identified in the related art. The siding panel hereof is preferably formed as an elongated panel having a front side and a rear side. The siding panel comprises a nail hem for securing the siding panel to a support structure. The nail hem includes a proximal laminae for mounting adjacent to the support structure and a distal laminae spaced from the proximal laminae and the support structure. The distal laminae terminates in a free end. The siding panel further includes a catch projecting outwardly from the panel. The catch serves as an impediment for the free end of the distal laminae thereby preventing further outward movement of the free end of the distal laminae